基于简化基因组测序的水牛遗传结构特征及选择信号分析

Genetic structure and selective signal analysis of buffalo based on simplified genome sequencing

  • 摘要: 【目的】 了解不同水牛群体的遗传多样性并确定各品种间的遗传关系,为后续的广西水牛保种选育及其特色性状形成机制研究提供理论依据。【方法】 分别采集摩拉水牛、尼里—拉菲水牛及杂交水牛(摩拉水牛与广西水牛杂交F1代)的颈静脉血液样本,通过Illumina HiSeqTM 2000测序平台进行简化基因组测序,采用主成分分析(PCA)结合血统分析揭示不同水牛群体间的遗传关系和群体结构,然后通过计算群体内的连锁不平衡衰减情况及群体间的固定系数(FST),筛选出与水牛经济性状相关的选择基因,并基于DAVID v6.8数据库进行KEGG信号通路富集分析。【结果】 3个水牛群体简化基因组测序获得的有效序列(Clean reads)比对到水牛第4版参考基因组(GCA_003121395.1)的平均比对率为99.54%;经SNP质控及过滤后,共获得2012270个SNPs。摩拉水牛与尼里—拉菲水牛间存在较大的遗传差异,群体内个体间也存在较远的遗传距离,其亲缘关系较远;相对于杂交水牛与尼里—拉菲水牛,杂交水牛与摩拉水牛的亲缘关系更近(FST均小于0.40)。3个水牛群体间的共有受选择基因有31个,且31个受选择基因主要富集于突触后膜和蛋白磷酸化通路上,共涉及5个基因,分别是AMPA型谷氨酸受体α1亚单位基因(GRIA1)、钾钙激活通道亚家族Mα1基因(KCNMA1)、Abelson小鼠白血病病毒癌基因同源物1基因(ABR)、TRIO Rho鸟嘌呤核苷酸交换因子基因(TRIO)及丝裂原活化蛋白激酶4基因(MAP4K4)。【结论】 基于简化基因组测序从摩拉水牛、尼里—拉菲水牛及杂交水牛3个群体中筛选出31个可能与水牛经济性状密切相关的候选基因,主要富集于突触后膜和蛋白磷酸化通路,其中GRIA1KCNMA1ABRTRIOMAP4K4等5个基因在神经调控和激素调节方面发挥着重要作用,通过神经系统、免疫反应和细胞行为等生物学过程间接影响水牛的体型、繁殖及泌乳性能。

     

    Abstract: 【Objective】 This study aimed to investigate the genetic diversity of different buffalo populations and determine the genetic relationships among breeds, so as to provide a theoretical basis for subsequent research on the conservation, breeding, and formation mechanisms of distinctive traits in Guangxi buffaloes. 【Method】 Jugular vein blood samples were collected from buffalo breeds Murrah, Nili-Ravi, and a hybrid (F1 hybrid of Murrah and Guangxi buffaloes). Simplified genome sequencing was performed using the Illumina HiSeqTM 2000 platform. Principal component analysis (PCA) and pedigree analysis revealed that the genetic relationships and population structure among different buffalo populations. Linkage disequilibrium decay and the fixed coefficient (FST) between populations were calculated to identify selective genes associated with economic traits of buffalo. KEGG signaling pathway enrichment analysis was conducted for these genes using the DAVID v6.8 database. 【Result】 The average alignment rate of the effective sequences (clean reads) obtained from the simplified genome sequencing of the three buffalo populations to the buffalo 4th version of reference genome (GCA_003121395.1) was 99.54%. After SNP quality control and filtering, 2012270 SNPs were obtained. A significant genetic difference was found between Murrah and Nili-Ravi buffaloes, with considerable genetic distance between individuals within the populations, indicating a distant relationship; compared to the hybrids with Nili-Ravi buffaloes, the hybrids with Murrah buffaloes were genetically closer (FST values all less than 0.40). A total of 31 shared selective genes were identified among the three buffalo populations, and they were mainly enriched in synaptic membrane and protein phosphorylation pathways, involving five genes: AMPA glutamate receptor subunit α-1 (GRIA1), potassium calcium-activated channel subfamily Mα-1 (KCNMA1), Abelson murine leukemia viral oncogene homolog 1 (ABR), TRIO Rho guanine nucleotide exchange factor (TRIO), and mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4). 【Conclusion】 Through simplified genome resequencing, 31 candidate genes potentially associated with economic traits of buffalo are identified from Murrah, Nili-Ravi, and hybrid buffalo populations. These genes are mainly enriched in synaptic membrane and protein phosphorylation pathways. Among them, GRIA1KCNMA1ABRTRIO, and MAP4K4 play important roles in neural regulation and hormonal regulation, indirectly influencing buffalo body size, reproduction, and lactation performance through biological processes such as the nervous system, immune response, and cell behavior.

     

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